Bugtraq mailing list archives
Re: [Full-disclosure] Microsoft DNS resolver: deliberately sabotagedhosts-file lookup
From: "John Biederstedt" <john () johnsdomain org>
Date: Wed, 19 Apr 2006 18:43:38 -0500
Actually, according to microsoft, the dns client in XP was *intended* to check to see if a dns lookup had failed earlier before going to the hosts file. We did ping the internal domain controller, added the bogus FQDN, and tried again. None of that worked, because prior to the VPN working, and lookup of the domain controller had failed, and been cached. So, because the failiure was checked before the hosts file, once the VPN was up, the dns lookups didn't work. Oh yes, the XP install was factory Dell.
--- Begin Message --- From: "Thor (Hammer of God)" <thor () hammerofgod com>
Date: Wed, 19 Apr 2006 15:22:32 -0700
Then you've hosed your XP install. XP does not resolve cached addresses before the hosts file. Ping your 1918 domain controller. Add a bogus entry for the FQDN of the same machine. Ping it again. Hosts file overrides. I'm not sure what you mean by "DNS failiures" though. Please post something we can all use to test your rotten but unsurprising behavior. Oh, and before getting very frustrated, even in your hosed install, just try a "IPCONFIG /flushdns" next time. t On 4/17/06 5:33 AM, "john () johnsdomain org" <john () johnsdomain org> spoketh to all:The XP DNS client has other problems as well. It caches DNS failiures (arguably out of spec with the RFC, BTW), screwing up VPNs if you're VPNed into an internet network that has local domains which need to resolve to RFC1918 addresses. The cached failed lookups get prefered to forced entries in the hosts file, if that is tried as a way of forcing the dns lookups to work. Very frustrating. So, this isn't much of a surprise. Rotten, yes, surprising, no.
--- End Message ---
Current thread:
- RE: [Full-disclosure] Microsoft DNS resolver: deliberately sabotagedhosts-file lookup Derek Soeder (Apr 14)
- Re: [Full-disclosure] Microsoft DNS resolver: deliberately sabotagedhosts-file lookup Thor (Hammer of God) (Apr 17)
- Re: [Full-disclosure] Microsoft DNS resolver: deliberately sabotagedhosts-file lookup Ansgar -59cobalt- Wiechers (Apr 18)
- Re: [Full-disclosure] Microsoft DNS resolver: deliberately sabotagedhosts-file lookup Paul Wouters (Apr 19)
- Re: [Full-disclosure] Microsoft DNS resolver: deliberately sabotagedhosts-file lookup Geo. (Apr 19)
- Re: [Full-disclosure] Microsoft DNS resolver: deliberately sabotagedhosts-file lookup Thor (Hammer of God) (Apr 23)
- Re: [Full-disclosure] Microsoft DNS resolver: deliberately sabotagedhosts-file lookup Geo. (Apr 23)
- Re: [Full-disclosure] Microsoft DNS resolver: deliberately sabotagedhosts-file lookup Thor (Hammer of God) (Apr 25)
- Re: [Full-disclosure] Microsoft DNS resolver: deliberately sabotagedhosts-file lookup Thor (Hammer of God) (Apr 17)
- <Possible follow-ups>
- Re: RE: [Full-disclosure] Microsoft DNS resolver: deliberately sabotagedhosts-file lookup john (Apr 19)
- Re: [Full-disclosure] Microsoft DNS resolver: deliberately sabotagedhosts-file lookup Thor (Hammer of God) (Apr 23)
- Re: [Full-disclosure] Microsoft DNS resolver: deliberately sabotagedhosts-file lookup John Biederstedt (Apr 23)
- Re: [Full-disclosure] Microsoft DNS resolver: deliberately sabotagedhosts-file lookup Thor (Hammer of God) (Apr 23)
- Re: [Full-disclosure] Microsoft DNS resolver: deliberately sabotagedhosts-file lookup John Biederstedt (Apr 23)
- Re: [Full-disclosure] Microsoft DNS resolver: deliberately sabotagedhosts-file lookup Thor (Hammer of God) (Apr 23)
- Re: [Full-disclosure] Microsoft DNS resolver: deliberately sabotagedhosts-file lookup Thor (Hammer of God) (Apr 23)
- Re: [Full-disclosure] Microsoft DNS resolver: deliberately sabotagedhosts-file lookup Thor (Hammer of God) (Apr 23)